Safety is the prerequisite element to quality care for emergency services relating to children. Safety events occurring during the emergency medical care outside the hospital are poorly understood and high quality epidemiologic data are lacking. Background: While quality and safety issues have been analyzed in the hospital setting, safety events have not been evaluated in emergency prehospital services. New technologies provide unprecedented opportunities to conduct epidemiologic and simulation studies. Aims: These studies aim to 1) identify reliable and valid measures for safety events in the prehospital care of children, 2) understand the incidence and contributors to safety events in the prehospital care for children, 3) understand individual, team, and systems issues that lead to safety events during in situ simulation of children's emergencies, and 4) establish a national system for the anonymous reporting of safety events. Methods: We will begin by conducting focus groups with Emergency Medical Services personnel and Emergency Department providers to characterize the range of and contributors to safety events in the EMS care of children. In turn, an expert panel will review a random sample of cases thought to be at high risk for a safety event (e.g., resuscitation, seizures, lights and siren transport) to develop screening and evaluation tools. These tools will be used to screen 1 year of pediatric EMS transports in a metropolitan area to identify safety events. All screen-positive records will be reviewed by an expert panel using a structured tool to confirm the safety event and assess contributing factors and preventability. In a complimentary approach, patient simulations will be used to evaluate the process by which safety events occur. Finally, we will develop a web-based reporting system to capture a broad range of safety events across all EMS systems: some of these events may be rare or undetectable in electronic records. Significance: This series of studies will exploit new technologies -- electronic records, simulation, and web-based reporting -- to develop a comprehensive understanding of safety events relating to the prehospital care of children. Identification of the factors contributing to safety events will inform improvements in training and implementation of safeguards to assure pediatric safety and quality in emergency care.